compromise/src/term/adjective/toComparative.js

natural language processing in the browser

//turn 'quick' into 'quickly'
'use strict';
const convertables = require('./paths').data.superlatives;

const irregulars = {
  'grey': 'greyer',
  'gray': 'grayer',
  'green': 'greener',
  'yellow': 'yellower',
  'red': 'redder',
  'good': 'better',
  'well': 'better',
  'bad': 'worse',
  'sad': 'sadder',
  'big': 'bigger'
};

const dont = {
  'overweight': 1,
  'main': 1,
  'nearby': 1,
  'asleep': 1,
  'weekly': 1,
  'secret': 1,
  'certain': 1
};

const transforms = [{
  reg: /y$/i,
  repl: 'ier'
}, {
  reg: /([aeiou])t$/i,
  repl: '$1tter'
}, {
  reg: /([aeou])de$/i,
  repl: '$1der'
}, {
  reg: /nge$/i,
  repl: 'nger'
}];

const matches = [
  /ght$/,
  /nge$/,
  /ough$/,
  /ain$/,
  /uel$/,
  /[au]ll$/,
  /ow$/,
  /old$/,
  /oud$/,
  /e[ae]p$/
];

const not_matches = [
  /ary$/,
  /ous$/
];

const to_comparative = function(str) {
  if (dont.hasOwnProperty(str)) {
    return null;
  }

  if (irregulars.hasOwnProperty(str)) {
    return irregulars[str];
  }

  for (let i = 0; i < transforms.length; i++) {
    if (str.match(transforms[i].reg)) {
      return str.replace(transforms[i].reg, transforms[i].repl);
    }
  }

  if (convertables.indexOf(str) !== -1) {
    if (str.match(/e$/)) {
      return str + 'r';
    }
    return str + 'er';
  }

  for (let i = 0; i < not_matches.length; i++) {
    if (str.match(not_matches[i])) {
      return 'more ' + str;
    }
  }

  for (let i = 0; i < matches.length; i++) {
    if (str.match(matches[i])) {
      return str + 'er';
    }
  }
  return 'more ' + str;
};

// console.log(to_comparative('big'));

module.exports = to_comparative;